Each year many people are turning to solar, some do this to help the environment, others do this to save money and a few do this because they think it is a new trend. But do you know what happens to unused electricity generated by solar panels?
Before installing a solar panel system, you need to decide what will happen to unused electricity generated by solar panels.
In this post, I am going to analyze what will happen to unused electricity generated by solar panels when you are connected to a grid ( on-grid system ) and when you are not connected to a grid (off-grid system).
Why there is excess electricity?
The excess electricity is produced due to the oversizing of the solar panel system. Sometimes maybe it was sized perfectly but there is a drop in electricity usage in the house ( some members of the family moved out, not using some electronic items that consume a lot of electricity, etc).
Whatever the reason, when the solar panels produce more electricity than you can use we need to figure out where to send it.
What Happens To Unused Electricity Generated by Solar Panels when you are on-grid?
If you have your solar panel system connected to a utility company grid, what will happen is that the utility company will have a bidirectional meter.
This is what industry experts call net metering, this is when you will be feeding the excess electricity to your utility company.
During the night or on cloudy days the utility company will feed electricity to your house, and at the end of the month, they will calculate the balance, if you fed the utility company more energy than you received they will give you a utility credit.
The amount of credit per kilowatt-hour will depend on your state, some will pay more some will pay less. This is a nice way to get paid for your solar panels.
In some countries like Mexico, the utility company will not give you cash, what they will do is they will store that energy for you, and when you need it they will give it back to you, but that storage is only valid for one year, that means after one year you can not claim that energy and the account will reset.
What Happens To Unused Electricity Generated by Solar Panels when you are off-grid?
When it comes to off-grid systems they need to be perfectly designed, this is because if they are undersized there is no grid to get electricity from and if they are oversized there is nowhere to send the extra electricity.
A well-designed off-grid system will have solar panels that effectively charge the batteries while supplying electricity to its electrical load.
The batteries will store the energy that will be produced during the day, and they will be used during the night and on cloudy days.
What happens if the batteries are full?
In an off-grid system, we depend on batteries to store extra electricity produced by solar panels.
If the batteries are full the solar power will be curtailed and be limited to what the load only requires.
Unfortunately, the extra energy from solar panels might not be converted into electricity and will be wasted most of the time.
Conclusion
What happens to unused electricity generated by solar panels depends on whether your solar panel system is connected to a utility grid or not.
If it is connected to the utility grid, it is easy, you use net metering and send the excess electricity to your utility company, they will either send you a check or pay back a kilowatt-hour per kilowatt-hour.
If you have an off-grid system, the excess electricity generated by your solar panels will be stored in batteries, and if the batteries are full solar power will be curtailed and the energy will be wasted.